55add5c Use anonymous Koji session properly

Authored and Committed by cqi 5 years ago
    Use anonymous Koji session properly
    
    MBS calls some read-only Koji APIs which does not require to log into a
    session. This patch makes it optional to choose whether to login a
    session and use anonymous session properly to call those read-only APIs.
    
    Signed-off-by: Chenxiong Qi <cqi@redhat.com>